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Schematic diagram and description of a magnetic loop antenna that works from 10 to 20 meters band, made from junk

The early 20th century saw significant advancements in wireless communication, culminating in the first successful transatlantic radio signal. This historical account details Guglielmo Marconi's pioneering efforts, from his initial experiments with electromagnetic waves to his patented wireless system in 1900. It describes the technical challenges of long-distance radio transmission, particularly the prevailing belief that radio waves would be lost due to the Earth's curvature over vast distances. On December 12, 1901, Marconi established a receiving station in Newfoundland, Canada, utilizing a _coherer_ and balloons to elevate the antenna. Signals, consisting of the Morse code letter "S" (pip-pip-pip), were transmitted from Poldhu, Cornwall, England. The successful reception of these faint but distinct signals across **1,700 miles** confirmed Marconi's theories, marking an epoch in communication history. This achievement demonstrated the viability of global wireless communication, paving the way for future developments in radio technology.

Operating magnetic loop antennas requires careful consideration of RF safety, particularly regarding near-field magnetic field intensity. This resource presents calculations for magnetic field strength (H-field) at various distances from a magnetic loop, emphasizing that the H-field is significantly higher than the E-field in the near-field region due to the inductive nature of the radiating element. It provides specific formulas and examples for determining safe operating distances based on power levels and loop dimensions, crucial for compliance with RF exposure limits. The analysis compares calculated H-field values against FCC and ICNIRP maximum permissible exposure (MPE) limits for controlled and uncontrolled environments. It demonstrates that even at QRP power levels (e.g., 5W), the H-field can exceed MPE limits within a few feet of the antenna, necessitating greater separation distances than often assumed for electric field considerations. The practical application of these calculations helps amateur radio operators configure their stations to ensure personnel safety and regulatory compliance when deploying compact, high-Q magnetic loop antennas.

Testing performances of indoor antenna. A comparison of a magnetic loop antenna vs a classic wire dipole done using wsprlite on 30 meters band.

Digital radio mondiale DRM products, measuring tools, Magnetic field probes, RF power meters, Broadband loop antennas, DRM devices and services

Magnetic Loop Antenna for 20/15m with Remote Tuning by George Szymanski

A magnetic loop antenna for the VHF band, featuring a high gain that can be compared to a quarter wave vertical antenna

A NEC Model Comparative Analysis of Physical Orientation and Performance. The small magnetic loop is a useful compromise antenna for limited space and portability. For this reason, the magnetic loop antenna is a practical high frequency antenna solution for the restricted space of apartment dwellers

Antennas and Accessories for Satellite Radio and AM FM HD Short Wave Radio, satellite antenna, shortwave magnetic loops.

Experimentig magnetic loop antennas for VHF and HF by M0UKD

A low-cost SWR meter project based on Arduino that works with AutoCap automatic antenna tuner for magnetic loop antennas

TSC International produces soft magnetic sheet steel, custom-stamped and heat-treated to achieve optimal electrical characteristics for applications such as motors, generators, linear power supplies, and ballasts. The company's manufacturing process focuses on precise material engineering to meet specific performance requirements in various electrical systems. They also specialize in soft magnetic core materials essential for transformers, chokes, and inductors. These core materials are utilized in power supplies, lighting ballasts, signal conditioning circuits, inverters, and battery chargers, providing critical magnetic properties for efficient energy conversion and signal integrity. Located at 39105 Magnetics Blvd, Wadsworth, IL 60083-0399, TSC International provides contact via sales@tscinternational.com or phone at +1 (0) 847 249 4900, facilitating direct inquiries regarding their magnetic component offerings.

Magnetic Loop antenna for 20 to 80 meters band using home made butterfly condensator kit

This Magnetic Longwire Balun (MLB) makes it possible to efficiently use a coaxial lead-in cable with all forms of longwires, T-forms or other types of wire antennas, without the need for an antenna tuner.

Octagonal magentic loop antennas that work from 20 to 10 meters with pictures and efficiency reports by G1KEA

The Ultimate Source for Electromagnetic Pollution Detectors, Shielding Devices and Protection Information

A few pictures of an homebrew magnetic loop RTX antenna project, working from 30 to 12 meters with excellent results

Home-Made Magnetic Loop Antenna for 30 Meters by WA8LMF

Understanding the operational impact of Broadband over Power Line (BPL) on amateur radio communications is crucial for any radio amateur, especially given the potential for significant radio frequency interference (RFI). This ARRL tutorial delves into the technical aspects of BPL, explaining how the technology operates by transmitting data over existing electrical power lines, which can inadvertently radiate broadband noise across various amateur bands. My own field experience, particularly on the lower HF bands, has often involved tracking down noise sources that exhibit characteristics consistent with BPL emissions, making this a pertinent topic for maintaining clear receive conditions. The resource further details the specific FCC rules and regulations implemented to restrict BPL deployment. These regulations aim to protect licensed radio services, including amateur radio, from harmful interference. It outlines the technical standards and operational limitations imposed on BPL systems to minimize their impact on the electromagnetic spectrum, a critical aspect for contesters and DXers alike. For those engaged in RFI mitigation, the tutorial provides a foundational understanding of the regulatory framework that can be leveraged when addressing BPL-related interference issues. It serves as a valuable reference for hams seeking to comprehend the technical challenges and regulatory solutions surrounding this pervasive noise source.

ARRL page dedicated to RF Safety

Solar Flux, Geomagnetic Activity indexes and interpreting their relation

Electroswitch Electronic Products specializes in the design and manufacture of various switch types, including rotary, toggle, pushbutton, and rocker switches, as well as encoders and indicator lights. The company provides commercial and MIL-spec compliant components, detailing features such as spring return, push/pull to turn, adjustable stop, concentric shaft, and keylock configurations for their rotary switch lines. Specific product series like the M5-series enclosed frame rotary switches are highlighted, demonstrating their engineering capabilities. The resource offers a Rotary Switch Configurator to assist customers in selecting appropriate components based on application requirements. It categorizes switches by construction, such as enclosed frame, open frame, military grade, sealed, subminiature, blade, and power options for rotary switches. Toggle switches are presented in miniature, full-size, military grade, and sealed variants, while pushbutton switches include ultra-miniature, miniature, standard, and sealed types. Further product details cover rocker switches in subminiature, miniature, and sealed configurations, alongside thumb switches. Encoder offerings include magnetic and mechanical types with options like concentric shafts and push-to-turn functionality. Indicator lights are available for both commercial rectangular panel mount and MIL-spec applications, featuring configurations such as Press-to-Test, Watertight, EMI Shielded, and Dimmable options.

Such kind of omnidirectional antenna gives the possibility to be QRV with horizontal polarisation, as commonly used for the CW and SSB section of the 2m band. This actual design shows a 1.3:1 bandwidth of about 150kHz, centered to 144.200MHz.

A considerably shortened Magnetic Loop antenna with performance of a single conductor text book magnetic loop.

Wideband receiving phased arrays with small electric or magnetic active wideband elements are discussed in details. Practical results and examples are given.

A page describing how to setup a magnetic loop antenna with the DIY Magnetic Loop Starter Kit produced by Chamaeleon Antenna. Includes a video and a detailed instructions to setup.

Electric Fields, magnetic fields, electromagnetic fields, losses, fresnel zone, nearfield and farfield

Operating Morse code (CW) relies on a diverse array of **telegraph keys**, each with unique characteristics and historical significance. This resource presents a personal collection of such keys, offering visual documentation and details on various models. It features early Marconi keys from the 1900s, including specific models like the Marconi Air Ministry Key and Marconi Coastal Station Keys, alongside **Vibroplex** bugs and JRC keys. The collection also highlights rare items such as the Brown Brothers Magnetic Twin Paddle Key, the Eddystone Bug Key, and Swedish SRA Ericsson Keys. Enthusiasts can view examples of GPO Double Current & Single Current Keys, Navy NATO Keys, and specialized aircraft and maritime keys. The site includes information on historical training devices like the OMNIGRAPH and a Morse Inker from 1900, providing context for the evolution of telegraphy equipment. Additionally, the resource showcases unique items like the B2 Spy Set SOE Agents Key and a WW2 Junker U-BOAT KEY, illustrating the varied applications of Morse keys throughout history. The author, G0RDO, also shares details on a home-made paddle key and invites inquiries for acquiring interesting Morse keys.

Tel-atomic sells physics educational apparatus, oscilloscopes, counters, magnetic meters

Magnetism is manifested as a 'field of vectors', that is, any point in the magnetic field has not only a magnitude, but a direction in space. The four Maxwell equations describe how electric and magnetic vector fields behave and interact.

A home made magnetic loop for HF Bands. This small and compact loop is designed to support small power transmissions on HF bands, from 7 MHz to 21 MHz

The Magloop Antenna Calculator was developed to predict the characteritics of a small-loop (aka magloop) antenna, given physical dimensions entered via slider widgets. This magnetic loop antenna calculator works also on most mobile devices, adjusting sliders and calculating dimensions in real time.

Preprinted from the 1997 ARRL Handbook for Radio Amateurs. Thermal Effects of RF Energy, Safe Exposure Levels, Cardiac Pacemakers and RF Safety, Determining RF Power Density

Maker of small and compact multiband QRP UltraLight Magnetic Loop Antennas and UnUn transformer for end-fed multiband antennas

The resource, "Conventional Use of Transmission Line," meticulously details the operational principles of transmission lines, emphasizing the Transverse Electromagnetic (TEM) mode of energy transfer. It clarifies that for a line to function purely as a transmission line, all currents must be confined internally, with external fields ideally zero. The discussion differentiates between balanced and unbalanced lines, asserting that while both require equal and opposite currents within the conductors, the key distinction lies in the voltage relationship of each conductor to the surrounding environment. It highlights that a good antenna pattern does not inherently confirm proper feeder balance, and that common-mode currents can lead to RF in the shack and increased noise levels, even without pattern distortion. The article further explains that a transmission line can become a radiating conductor if energy is applied in a non-TEM mode, leading to common-mode issues. It cites classic texts like Jordan and Balmain's "_Electromagnetic Waves and Radiating Systems_" and Kraus's "_Antennas_" to support its definitions of TEM mode operation. The content also explores non-transmission line applications of parallel or concentric conductors, such as _coaxial dipoles_ and _folded dipoles_, which intentionally operate in non-TEM modes for antenna functionality. The author, _W8JI_, stresses that simply measuring equal currents is insufficient to confirm a balanced feeder; phase and voltage balance to ground are equally critical.

The video delves into the fascinating science behind antennas, which are crucial for receiving and transmitting electromagnetic waves. It explains how antennas convert electric signals into electromagnetic waves for transmission, and how they operate through the oscillation of positive and negative charges in dipole arrangements. Practical antenna implementations, such as dipole antennas for TV reception and Yagi-Uda antennas with reflectors and directors, are also discussed alongside modern dish TV antennas with parabolic reflectors for signal processing. It's a comprehensive overview of how antennas work and their significance in communication technology.

A 160 Metre Transmitting and Receiving Thin Wire Magnetic Loop Capable of DX. Designed and Patented by Ben Edginton G0CWT

This EXCEL Program Worksheet calculates the safe operating conditons for a toroidal transformer operating between 1 and 50 MHz. Manufacturer data for complex permeability, magnetic dimensions, and saturation flux density must be available. Some core types which are commonly used in amateur transmission are included. The program produces limiting winding voltages for linear operation and temperature rise over the range of frequencies and power specified.

NJ2X is a licensed amateur radio operator (FCC Amateur Extra) who enjoys casting electromagnetic waves into the ether. NJ2X pursues many aspects of the hobby including chasing DX, participating in mini-DX expeditions, building equipment and antennas, and papering his shack walls with ARRL awards. NJ2X dedicates this amateur radio oriented site to helping others who also enjoy the greatest of scientific hobbies. The site is suitable for all readers - families, the young, and the young at heart.

A small, easy to build, copper tube magnetic loop antenna for the 2 meters band. In Italian

Manufacturer of amplifier for small magnetic and electric receiving wideband antennas, and variable delay line kit for active antenna phased arrays

Basic magnetic loop antenna examples and loop aerials theory explained. This article inclued some interesting tricks on building magnetic loop antennas and an usefull excell sheet to help compute magneti loop antennas calculating power efficiency from 10 to 40 meters band

A dynamic collection of high latitude geomagnetic data from 12 Canadian observatories

This magnetic loop DIY site is ment to be an introduction into making DX high quality magnetic loop antennas that will beat any dipole

No matching adjustments needed. Directly perfect match to 50 Ohms using a remotely switched wideband transformer

The BikeLoop antenna project details the construction of a double magnetic loop antenna optimized for VLF frequencies, specifically around 136 kHz. This innovative design incorporates two orthogonal loops, which significantly enhance reception capabilities. Key construction hints include utilizing lightweight bicycle rims for the antenna structure, making it easy to transport and set up in various locations. The document provides valuable mathematical and electrical insights into the antenna's performance, alongside practical reception tests conducted in the Italian Alps, showcasing its effectiveness in capturing various VLF signals, including Sferics and FSK transmissions. Proper setup is crucial for optimal performance. The project emphasizes the importance of grounding and avoiding interference from nearby electrical sources. The reception tests revealed the antenna's ability to capture a range of signals, demonstrating its practical application for enthusiasts interested in VLF reception and antenna experimentation. Overall, the BikeLoop serves as an excellent starting point for those looking to explore the world of VLF frequencies and enhance their antenna-building skills.

The magnetic loop, thus named by the use of the magnetic component of the electromagnetic field, is a parallel circuit LC. In this article a sample project to home made a custom antenna. The circular form is often met on the commercial models but this antenna can be hexagonal, octagonal or square.

I wanted to mount an amateur radio antenna on my truck that was more permanent than the magnetic mount on I already had, but I had a few specific design requirements for the project.

High-performance rugged antennas and RF accessories such as magnetic mounts, RF coaxial gooseneck adapters, LNAs, BDCs, for law enforcment, military, maritime and video markets.

A magnetic loop antenna designed for 14 MHz. This kind of antennas is also known as STL, small transmitting loop and can be an excellent solution when you are not allowed to put antennas on your roof